Woody species diversity potential and population structure across the small-scale agroforestry farming system of the Midakegn District, West Shewa Zone, Ethiopia

Abstract

Biodiversity in agroforestry systems contributes to diversified socio-economic and cultural dimensions and to managing biodiversity. Agroforestry is one of Ethiopia's highest conservation priorities to promote forest-based ecosystem services and environmental incentive programs that minimize deforestation. This study was carried out across intensively cultivated areas of Midakegn district to assess the woody species diversity potential of agroforestry systems managed by farmers. Out of 114 plots laid down on transect lines, 33 (30 m×30 m), 44 (50 m×50 m), and 9 (10 m×10m) plots belonged to grazing land, cropland, and woodlots, respectively, and 28 representative homegardens were systematically selected. For each sample of data encountered, the diameter and height of woody species were measured. Species richness, Shannon diversity, and evenness indices were used for diversity analysis and the mean values/land unit were calculated using a one-way ANOVA, and Tukey's pairwise comparison was done through SPSS statistics at (P < 0.05). A total of 77 species belonging to 68 genera and 45 families were recorded in all agroforestry systems. Species richness was significantly affected by study site, land use type, and wealth class, and evenness was significantly affected by land use type and wealth class. But species diversity was only affected by land use type. The highest mean density/hectare (8244.44 and 1263.17) and basal area/hectare (85.68 and 19.00) were recorded in the woodlot and rich homesteads, respectively, while the lowest mean density/hectare (9.82 and 48.16) and basal area/hectare (2.27 and 1.40) were computed for the cropland and poor homesteads, respectively (P < 0.05). The results confirmed that different agroforestry systems have great potential in conservation woody species, particularly native plant biodiversity. Hence, there is a need to promote and enhance the system through a development and management approach to maintain more biodiversity.